Fire alarm



Oct. 20, -1959 J. s. sTAMM ET AL FIREALARM Filed Aug. 15, 195'? Joseph 5. Sfamm Wilford 6. Bennett INVENToRs, mw- BY @uw WWW Mm United States Patent C) FmE ALARM Joseph S. Stamm and Wilford G. Bennett, Baltimore, Md.,

assignors to F & G Supply Co., Baltimore, Md., a corporation of Maryland v This invention relates to an electrical alarm system and actuator therefor and more particularly to a tire alarm circuit closing device. l

The primary object of the present invention is to provide a Contact closing device for completing an operative electrical circuit between a source of power and an alarm device which contact closing device may be easily and conveniently secured on a conventional conductor such as a twin-lead conductor or the like.

A further object of the invention is to provide a fire alarm actuation device which includes means for securing the device on a twin lead electrical conductor for completing an operative electrical circuit between a source of power and an alarm device without the necessity of cutting the insulation away lfrom the conductor and without the necessity of separately attaching the conductors to terminals on the actuation device.

A further object of the invention is to provide a small and efficient circuit closing device which is no larger than the ordinary plug type electrical connector, which includes not only a bi-metallic switch but also a mechani- Figure 1 illustrating those parts of the invention in which the closure member is locked to the housing.

With continuing reference to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, reference numeral 10 generally designates one of the circuit closing devices utilized to actuate the re alarm in accordance with the concepts of the present invention. This circuit closing device 10 may be positioned at any point along a twinlead conductor 12 or any other suitable electrical conductor. It is within the concept of the present invention to connect one of the leads of the twin-lead electrical conductor 12 to one prong of an electrical connector plug, the other of the prongs of the plug, not shown, being connected to a conductor 16 which is `electrically connected to a bell 18 or other suitable audible alarm. It

cal switch held out of circuit closing position by means l of a meltable substance such as sealing wax.

Further objects and features of this invention reside in the provision of a re alarm including actuation devices which may be produced at a Very low cost thereby permitting ywide use and distribution, which may be attached at any place on a conductor without requiring that the conductor be detached from an installed position, and which is simple to install and easy to use. These, ytogether with the various ancillary objects and features of the invention which will become apparent as the following description proceeds, are attained by this re alarm actuation device, a preferred embodiment of which has been illustrated in the accompanying drawings, by way of example only, wherein:

Figure 1 is an elevational view somewhat diagrammatic and with certain concealed parts shown in dotted lines of -the re alarm system comprising the present invention;

Figure 2 is a vertical transverse sectional view taken substantially along the plane of the line 2-2 in Figure 1 illustrating in particular the relative arrangement of the various parts employed in the circuit closing device of the invention;

Figure 3 is in enlarged perspective view of the circuit closing device with `parts thereof being broken away to show other parts in section and further illustrating the contact making and breaking elements in detail; and

Figure 4 is a sectional detail View taken in vertical transverse section along the plane of the line 4-4 in is to be understood that in addition to or in place of an audible alarm, visual alarms, not shown, may be employed. The plug is to be connected to a source of electrical power as suggested at 14 and the alarm or bell 18 is connected to a conductor 20 to the other conductor of the twin-lead conductor 12 so that when a circuit is closed between the conductors vof the twin-lead conductor, an operative electrical circuit will be completed from the source of electric power to the alarm.

The circuit closing device 10 is adapted to close the circuit between the source of electrical power to the alarm device 18 by completing an operative electrical circuit between the conductors of the twin-lead conductor upon subjection to a predetermined amount of heat.

The actuating device 10 includes a housing 24 of any suitable shape which is shown as open at its lower end. The housing is provided with a pair of tongues or ribs 26 and 28 on the lower sides thereof as shown in Figures 2 4, and has depressions disposed in the sides thereof as indicated at 30 and 32 in Figure 4 above the tongues 26 and 28.

A generally channel-shaped closure member 34 is provided for closing the open lower end of the two side walls of the housing 24 and includes grooves as at 36 and 38 in the inner side walls corresponding to the tongues 26 and 28 and adapted to receive the tongues therein, In order to provide means for locking the channel closure member 34 in place, lugs 40 and 42 are integrally formed on the inner faces of the side walls of the channel shaped closure member 34 and are adapted to be engaged within the recesses 30 and 32. It is to be recognized that the material from which the housing is constructed is of such a nature as to resiliently yield while the channel-shaped closure member 34 is being positioned on the housing and yet arranged so as to lockingly hold the channel member when in a locked position.

The channel member is adapted to have the twin-lead conductor 12 positioned thereon and when the closure member 34 is pushed to its above mentioned locked position on the open end of the housing, it will cause'the piercing edges -50 and l52 of contact plates `54 and 56 respectively to penetrate separate conductors of the twinlead conductor 12. The plates 54 and 56 are mounted with their side edges extending into grooves, not shown, in the side walls of the housing 24 or otherwise positioned therein and it is noted that the contact plate 56 has a contact plug `60 extending through the top wall .of the housing 24.

The housing 24 is further provided in an end wall with an aperture 62 in which a rod `64 is slidably mounted. The rod is provided with a head as at 66 outside of the housing and has a contact 68 mounted thereon inside the housing. A spring 70 coaxial with the rod 64 abuts the inner wall of the housing and the contact 68 normally urging the contact 68 to a position engaging the contact plate 54 and the rod to a position where its extremity engages the contact plate 56 to complete an operative electrical circuit between the contact plate 54 and the contact plater56, it being noted that the rod 64 and the contact 68 are of electrically conductive materials.

1n order to prevent the spring 70 from functioning to close the operative electric circuit between the contact plate 54 and the contact plate 56, a piece of sealing wax 72 or other suitable meltable substance is positioned between the head 66 and the housing 24. When heat is applied sucient to melt the sealing wax "72, the circuit will close.

However, it is possible that a nre willl be located at a point remote from the housing so that the sealing wax will not be quickly enough melted for actuation yet the heat is -sufiicient to desire that the device function. In order to assure proper functioning of the device and in any event that the spring 70 may be inoperative to cause a closure of the circuit, there is provided a bi-metallic switch consisting of a bi-metallic element 80 riveted as at 82 to an end wall of the housing 24 and which overlies the housing top wall and is adapted to coact with the lug `6i) upon the latter to complete an operative electrical circuit from the contact plate 54 to the contact plate S6, it being noted that a conductor 86 interconnects the bi-metallic strip` 80 with the contact plate 54.

The use of this invention is self-evident. The bell and the plug being connected toa manner heretofore described, the devices can be installed at any points along the twin-lead conductor and serve to protect the areas in which they are located.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:`

l. A re alarm circuit closing device comprising an electrically insulative housing having an open end, a closure member detachably secured to said housing, said housing and said closure member being adapted to clampingly engage a pair of electrical conductors, a first contact plate disposed in said housing and having piercing means for engaging one of said pair of electrical conductors, a second contact plate disposed in said housing spaced from said first contact and having piercing means for engaging the other of said pair of electrical conductors, said housing having an aperture therethrough, an electrically conductive rod extending through said aperture and having a head outside of said housing, a contact on said rod in said housing, a meltable substance disposed between said head and `said housing, a spring engaging said contact and said housing urging said rod to a position engaging said first contact plate and with said contact engaging said second contact plate to complete an operative electrical circuit between said first contact plate and said second contact plate.

2. A fire alarm circuit closing device comprising a housing of electrically insulative material, a first contact plate disposed in said housing, a second contact plate disposed in said housing and spaced from said first contact plate, said housing having an aperture therethrough, an electrically conductive rod extendingthrough said aperture and having a head outside of said housing, a :contact on said rod in said housing, a meltable substance disposed between `said head and said housing, a spring engaging said contact and said housing unging said rod to a position engaging said first contact plate and with said contact engaging said second contact plate to complete an operative electrical circuit between said first contact plate and said second contact plate.

3. A fire `alarm circuit closing device comprising a housing of electrically insulative material, a first contact plate disposed in said housing, a second contact plate disposed in said housing and spaced from said first contact plate, said housing having an aperture therethrough, an electrically conductive rod extending through said aperture and having a head outside of said housing, a contact on said rod in said housing, a meltable substance disposed between said head and said housing, a spring engaging said contact and said housing urging said rod to-a position engaging said first contact plate and with said contact engaging said second contact plate to complete an operative electrical circuit between said first contact plate and said second contact plate, a bi-metallic strip secured to said housing and electrically connected to said second contact plate, said first contact plate having a contact lug forming a part thereof extending through said housing, said bimetallic strip `being engageable with said contact lug to complete an operative electrical `circuit between `said first contact plate and said second contact plate.

4. A fire alarm circuit closing device comprising an electrically insulative housing having an open end,` .a closure member detachably secured to said housing, said housing and said closure member being adapted to clampingly engage a pair of electrical conductors, a first contact plate disposed in said housing and having piercing means for engaging one of said pair of Velectrical conductors, a second contact plate disposed in said lhousing spaced from said first yContact and having piercing means for engaging the other of said pair of electrical conductors, said housing having an aperture therethrough, an electrically conductive rod extending through said aperture and having a head outside of said housing, a contact on said rod in said housing, a meltable substance disposed between said head and said housing, a spring engaging said contact and said housing urging said rod to aV position engaging said first contact plate and with said contact engaging said second contact plate to complete an operative Velectrical circuit between said first Contact plate and said second contact plate, a bimetallic strip secured to said housing and electrically connected `to said second contact plate, said first contact plate having a contact lug forming a partthereof extending. through said housing, said bimetallic strip being engageable with said contact lug to complete an operative electrical circuit between said rst contact plate and said second con tact plate.

5. The combination of claim 2 wherein said `housing has parallel side walls with said first and second contact plates being lixedly secured thereto in parallel relation to each other, said rod being disposed substantially perpendicular to Said contact plates. l

6. The combination of vclaim 2 wherein said housing has parallel side walls with said first and second contact plates being iixedly secured thereto in parallel relation to each other, said rod being disposed substantially perpendicular to said contact plates, said second contact plate being shorter than said first contact .plate with said `rod lbeing positioned in spaced relation at all times to said second contact plate.

7. The combination of claim 2 wherein said housing has parallel side walls with said first and second .contact plates being fixedly secured thereto in parallel relation to each other, said rod lbeing kdisposed substantially .perpendicular to said contact plates, said 'firstcontact'plate having its upper-end extending Athrough a Wall of said housing and having a contact lug thereon, a bimetallic strip secured to .the exterior of said housing and thermally operable into engagement with Vsaid lug, means eleel trically connecting said bimetallic strip to said second contact plate.

8. The combination of claim 2 wherein said housing has parallel side walls and a closed top wall with an open bottom, laterally projecting ribs along said side walls, a 5

channel closure for said open bottom having parallel resilient flanges embracing said side walls, said llanges having channels receiving said ribs.

9. The combination of claim 2 wherein said housing has parallel side walls and a closed top wall with an open 10 bottom, laterally projecting ribs along said side walls, a channel closure for said open bottom having parallel resilient flanges embracing said side walls, said anges having channels receiving said ribs, said side walls having grooves extending vertically upwards from said ribs, projections on said anges engageable in said grooves.

References Cited in the le of this patent UNITED STATES PATENTS 454,746 Leonard June 23, 1891 1,977,191 Levenstein Oct. 16, 1934 2,204,237 Slack et al. June 11, 1940 2,552,331 Lamb May 8, 1951 FOREIGN PATENTS S29948x/39a Germany Mar. 15, 1956 

